1. Field of the Invention
The present invention relates to a tubing connector. In particular, the invention relates to an expandable tubing connector.
2. Description of the Related Art
In the oil and gas exploration and extraction industry, well bores are lined with metal tubing. Typically, the majority of a well will be lined with tubing known as casing, while the distal end of the well is provided with smaller diameter tubing known as liner. Generally, the section of the well provided with the liner will intersect the hydrocarbon-bearing formation.
Both the casing and the liner will typically be formed of tube sections with threaded or otherwise formed ends, such that the tube sections may be joined end-to-end to form longer tubing strings. The tube section ends may be formed to provide male and female coupling portions, generally known as pin and box couplings, or may be formed as male portions adapted to co-operate with external connectors or sleeves.
In recent years there have been numerous proposals to provide downhole tubing which is expanded downhole, that is casing, liner or other tubing of a first diameter which is run into a bore and then expanded to a larger second diameter. However, difficulties have been experienced in creating tubing connections which will maintain their integrity following expansion. In particular, threaded connections tend to loosen or separate on expansion, and there have been numerous proposals for connections with, for example, different thread forms, with a view to countering this difficulty.
It is among the objectives of embodiments of the invention to provide an expandable tubing connector which will maintain integrity post-expansion.